Texas Instruments Announces the New bq2019 Battery Monitor IC
Texas Instruments (TI, Dallas, TX) is announcing a new Power Minder IC, the bq2019, a battery monitor, which they claim will allow users of battery-operated, portable devices to know the exact amount of their battery's remaining charge and discharge times. Designed for battery-pack integration, this new IC allows designers to implement battery monitoring while eliminating the need for an identification chip and temperature thermistor.
The device, which features 96 bytes of on-board flash memory and 1 degree C temperature sensing, can be used in cellular phones, Internet audio players, personal digital assistants and other hand-held electronics. It works with a range of battery chemistries, including lithium-ion, lithium-polymer and nickel-metal hydride. TI maintains that the bq2019 provides accurate reading of the remaining charge by measuring the battery current over time, and working with the host processor to make calculations of remaining battery capacity. It reads the voltage from an external low-resistance, current-sense resistor in series with the battery. That voltage then feeds an on-chip voltage-to-frequency converter (VFC) to integrate charge and discharge currents.
To improve accuracy, the VFC features automatic offset correction to cancel circuit offset measurement error to less than 10uV. The small measurement offset area allows the use of a low-value sense resistor to measure a wide range of charge/discharge currents while minimizing battery voltage drop. In this way, the system can tell users how much operating or standby time remains before the battery runs down or how much time it will take for the battery to reach full charge. In addition, the system can use information from the bq2019 as an input to its power-management routine to more efficiently manage battery power versus user demand of system resources and peripherals in an effort to extend system operating time as much as possible.
Consumers are continually frustrated with not knowing the exact amount of battery time remaining in their portable applications," said Peter Fundaro, marking manager of battery-management products at TI. "With the bq2019, manufacturers can now provide this critical information to users while still meeting the cost and functional requirements for battery packs in portable consumer applications."
The bq2019 is housed in an eight-pin TSSOP package and consumes only 80uA when active and less than 1.5uA in sleep mode. TI plans to make it available in volume by the end of October 2000, at a resale price starting at $2.40 each in quantities of 1,000.
